Frequency Stability: What Does 2 Parts in 10E10 Mean?

  • Context: Undergrad 
  • Thread starter Thread starter Stu165
  • Start date Start date
  • Tags Tags
    Frequency Stability
Click For Summary

Discussion Overview

The discussion revolves around the meaning of the term "frequency stability" in the context of lasers, specifically the phrase "2 parts in 10E10." Participants explore how this terminology relates to frequency shifts and seek clarification on its implications.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the meaning of "2 parts in 10E10" and suggests it indicates a frequency shift of 0.02nm around the mean wavelength.
  • Another participant explains that the shift is typically expressed as a normalized shift relative to the central laser frequency, represented by the equation \(\frac{\Delta\nu}{\nu_0}\), which is dimensionless.
  • A different participant acknowledges familiarity with the equation but expresses confusion about the specific terminology used and how to derive the shift from it.
  • One participant provides the equation \(\frac{\Delta\nu}{\nu_0} = 2 \times 10^{-10}\) and notes that knowing the central frequency allows for the calculation of the exact amount of shift.

Areas of Agreement / Disagreement

Participants express differing levels of understanding regarding the terminology and its implications, indicating that there is no consensus on the clarity of the term "2 parts in 10E10" and its practical application.

Contextual Notes

There are unresolved questions about the terminology and its interpretation, as well as the dependence on the central frequency for calculating the actual shift.

Stu165
Messages
10
Reaction score
0
Does anyone know what it means to say that the frequency stability of a laser is 2 parts in 10E10, I gather that it means that the frequency shifts 0.02nm each side of the mean wavelength. But I can't find any resources that use the term parts.
 
Physics news on Phys.org
The shift is usually expressed as a normalised shift w.r.t. the central laser frequency.

[tex]\frac{\Delta\nu}{\nu_0}[/tex]

This quantity is dimensionless and thus has no units.

Claude.
 
I know that equation and all the coherence stuff, it's just the terminology of 2 parts in 10e10, has thrown me and how to get the shift from that.
 
Well,

[tex]\frac{\Delta\nu}{\nu_0} = 2 \times 10^{-10}[/tex]

If you know the central frequency of the laser, you can figure out the exact amount of shift.

Claude.
 
Last edited:

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
12K
  • · Replies 9 ·
Replies
9
Views
5K
Replies
1
Views
2K
  • · Replies 11 ·
Replies
11
Views
6K
  • · Replies 1 ·
Replies
1
Views
5K